Field of the Invention
This invention relates to a method of and an apparatus for measuring forces or moments, or both, in at least three mutually perpendicular directions. More particularly, this invention relates to a method of controlling a robot arm or operator in response to force or moment measurements in a plurality of directions on such robot arm or operator when it encounters resistance to movement in a given direction. As used herein, a "moment" is a torque, twist, or rotary force acting around an axis in a given direction.
In automatically controlled apparatus and particularly in robotic machinery, it is desirable to monitor the forces and moments being generated at the work site between the motive or drive power element and the driven element of the operating unit, frequently referred to as an "arm". Force and moment measurements and feedback (control in response to such measurements) have heretofore been accomplished by a number of methods. For example, individual axial forces have been measured with a standard moment measuring loadcell. For simultaneous measurement of more than one load or moment, single force or single moment loadcells have been assembled with suitable mechanical devices to achieve the required loading measurements.